Since EE 4.0, 4.1
The theme component can be used to change the ACE ThemeRoller theme used by the page this component is defined in. It overrides the initial/default theme set by a context param as detailed in http://www.icesoft.org/wiki/display/ICE/ace.theme, which also describes the location and naming of the theme stylesheet files.
<ace:theme value="trontastic"/>
This will select the 'trontastic' theme for the page where this tag is put in.
TagLib Documentation
This section covers attributes involved in the typical use-cases for this component.
value: the name of the theme as described in the link in the Overview above. Note: the value "none" will disable theming.
The theme specified in the org.icefaces.ace.theme context parameter will be used as the theme for the current user, whenever this component is missing from the page. If the value of this context parameter is null as well, then the sam theme will be used by default. If the value of this parameter is none, then no theme will be used at all.
None.